1. Field of the Invention
Catalysts provided by mixtures of certain magnesium-containing compounds and manganese-containing compounds are well known. There is herein described a catalyst of particular interest which is derived from a novel precursor made by depositing manganese hydroxide on a magnesium-compound matrix and which is particularly effective in a process for ortho-alkylating phenolic compounds.
2. State of the Art
In U.S. Pat. No. 3,873,628 of Van Sorge, an ortho-alkylation catalyst is prepared by mixing magnesium oxide with aqueous manganese sulfate, heating the mixture till dry and then calcining the dried mixture. In U.S. Pat. No. 3,972,836 of Van Sorge, an ortho-alkylation catalyst is prepared by dry blending magnesium oxide and manganese oxides, wherein the manganese hydroxides may be precipitated from an aqueous solution of manganese sulfate and potassium hydroxide. In U.S. Pat. No. 4,041,805 of Frabetti, an ortho-alkylation catalyst is described which comprises a mixture of magnesium oxide and magnesium oxide. The magnesium oxide component is derived by thermal decomposition of magnesium carbonate, basic magnesium carbonate or magnesium hydroxide. The manganese oxide component is derived as a precipitate from a solution of manganese sulfate and potassium hydroxide.
All of the catalyst materials described in the aforementioned patents suffer disadvantages either in catalyst preparatory methods or in use of the catalyst in an ortho-alkylation process. For example, the Van Sorge '628 catalyst containing sulfate anion generates significant amounts of mercapto-containing compounds which may be highly offensive to the environment. The later Van Sorge '836 patent specifically teaches that the catalyst materials must be washed repeatedly with an alkaline solution in order to remove both sulfate and potassium ions.